I have an airport express can I connect it directly to a modem, extend from there to another room i.e. my Office and then use a time capsule

I have an airport express can I connect it directly to a modem, so I can use this downstairs for wifi and then run ethernet cable form it upstairs to my Office and then connect it to a time capsule or Airport extreme.
If this is a good way to do it what would be the best modem? UK on virgin broadband NOT cable :(
OR is there a better way??????